To power output and thermal efficiency of an internal combustion engine and to exhibit higher performance, fluid such as air has been injected into a combustion chamber at a later stage of a combustion stroke. Further, a small toroidal chamber, i.e., an energy cell, has been formed in a cylinder head of previously known internal combustion engines.
In the prior art described above, efficient combustion cannot be achieved because of the complicated structural configuration required, and therefore performance of the internal combustion system does not reach the desired level.
It is an object of the present invention to provide an improved piston structure for use in an internal combustion engine capable of improving combustion in a combustion chamber so as to obtain higher performance from the engine.